TAMPA — Kay Nash stood beside the white dry-erase board, her equations creeping sideways like fiddler crabs on a beach. A 17-year veteran and chairwoman of the mathematics department at Tampa Bay Technical High School, this is where she lived.

At Tampa Bay Tech, students often take math, including Advanced Placement calculus, to prepare for careers ranging from commercial art to engineering. Florida Comprehensive Assessment Test scores show 82 percent of the school's students at or above their grade levels in math.

In recent years, school officials discussed devoting more resources to shoring up weaker areas for the FCAT, such as reading or science. Mrs. Nash objected. "She blew a gasket," said Scott Brooks, Tampa Bay Tech's principal, who called Mrs. Nash "definitely one of the leaders on campus."

Students saw her as a fount of patience.

"She could teach it to you once, and you could completely zone out and say, 'I didn't understand a word you said,' " said Jeff, 17. "And she would teach it to you again."

Whether they knew it or not, students have had to share Mrs. Nash for the last decade with an intruder: cancer. Doctors removed a lump on her breast in 2000. When the cancer returned in 2008, she underwent a double-mastectomy and took more than half the school year off.

The specter of the disease loomed after she returned to work in 2009, but only a few colleagues knew its extent. Mrs. Nash underwent chemotherapy and radiation, but stuck to her routine. Several times, she and Ken escaped to the mountains of North Carolina. "I guess you could say she lived an 80 percent normal life," her husband said. But doctors had told Mrs. Nash that her disease was spreading.

On Sept. 23, a Thursday, Mrs. Nash told the math team she would not attend school Friday.

The next day, Mrs. Nash drove herself to University Community Hospital. Her husband, who had been attending an out-of-state funeral, returned. She was moved to Moffitt late Saturday.

At 1 a.m. Sunday, Ken Nash was about to leave her room at Moffitt so his wife could rest.

"The last thing she asked me," he said, "was to bring her her calculus book so she could work on lesson plans."

Mrs. Nash died at 10:45 a.m. that day.

Darius Banner said he ducked into a bathroom when he heard the news. "I cried like a little baby."

After the flagpole ceremony, students raised money for the American Cancer Society, in honor of a teacher who was still trying to reach them the last day of her life.